A number of structures and methods are known and commonly used to install an elevator entrance sill including the following:                “sill support pocket”. This method is typically used in a building where the structural method of support is poured concrete. The concrete hall floor slab extends into the shaft and a pocket approximately 2″ to 3″ deep must be created in the top edge of the slab inside the elevator shaft in the opening A where the entrance is to be located. Making a pocket is a time consuming and costly procedure. The sill is fastened to this pocket by means of adjustable brackets and eventually the whole entrance is mounted on top of the sill. There are a number of common problems with this cumbersome and inefficient method:        (a) When the floor is poured, the contractor forgets to build the pocket into the form used to shape the floor slab. The concrete must then be chopped out manually, a time consuming and inaccurate process.        (b) The pocket is formed unevenly or inaccurately because the tolerances for pouring concrete are much larger than those in entrance installation. Installation now takes longer to adjust the entrance components and specially made parts may be required.        (c) Because the sill adjustment angles leave a large empty space under the sill, cement must be poured under the sill in order to minimize deflection when a heavy load is run over the sill or from sagging over time due to traffic. If the sill is allowed to bend too much the doors can come out of their tracks and fall off the entrance, leaving an open shaft.        
“sill support angle”. This method is typically used in a building where the structural method of support is steel. Since the floor slab does not extend into the shaft, L-shaped structural steel angles are bolted into the shaft wall a few inches below the floor at each opening. The sill is then mounted on this angle using adjustable brackets. The most significant disadvantage is that this can only be done from a running elevator platform (when the elevator's mechanical and electrical systems are installed). This presents the following problems:                a. Using the running elevator platform for sill support angle installation prevents other trades from using it. The elevator construction company cannot make any adjustments on the elevator's performance, nor can the platform be used to bring other material up and down within the building.        b. When the platform is being used the elevator company cannot work in the shaft.        c. Trade union regulations require that only a qualified operator can operate the platform, but this operator cannot assist in installing the sill support angles, thereby adding extra cost to the entrance installation.        d. Because the sill adjustment angles leave a large empty space under the sill, cement must be poured under the sill in order to minimize deflection when a heavy load is run over the sill or from sagging over time due to traffic. If the sill is allowed to bend too much the doors can come out of their tracks and fall off the entrance, leaving an open shaft.        “continuous strut/beckett system”. This method of erection can be used in any type of building. Sections of struts, U-shaped or L-shaped channels, are spliced together to run continuously the whole height of the shaft parallel to the elevator rails, one strut on either side of the entrance opening. The struts are bolted to the wall periodically to allow them to hold the entire weight of the entrance assembly. Just below the opening at each floor, a sill mounting channel is installed horizontally and fastened to each strut. This sill is then installed on this channel and adjusted to the correct height. The primary problem with this method is that the struts and the sill mounting channel can only be installed from inside the shaft. As mentioned in the “sill support angle” description, this presents the following problems which increase expense and complexity:        a. Using the running elevator platform for sill support angle installation prevents other trades from using it. The elevator construction company cannot make any adjustments on the elevator's performance, nor can the platform be used to bring other material up and down within the building.        b. When the platform is being used the elevator company cannot work in the shaft.        
Accordingly there has been a need for a simple, inexpensive structure and method of sill installation that overcomes the above disadvantages.